Published: Tue, November 21, 2017
Hi-Tech | By Ellis Neal

Known Interstellar Object Looks…Pretty Weird

Known Interstellar Object Looks…Pretty Weird

When astronomers using the Pan-STARRS1 telescope in Hawaii spotted a mysterious object dashing through our solar system on October 19, they immediately knew it was something special.

New data from the European Southern Observatory's telescopes and others around the world have revealed that the asteroid - spotted last month, already speeding away from the sun - is rocky, cigar-shaped and about 400 metres long.

Although 'Oumuamua formed around another star, scientists think it could have been wandering through the Milky Way, unattached to any star system, for hundreds of millions of years before its chance encounter with our Solar System. Any further studies will be key given that interstellar asteroids are faint and hard to spot despite the fact that they likely pass through the inner solar system about once a year.

"This history-making discovery is opening a new window to study formation of solar systems beyond our own", he added. The orbit calculations revealed beyond any doubt that this body did not originate from inside the Solar System, like all other asteroids or comets ever observed, but instead had come from interstellar space.

From there, no-one knows.

If planets form around other stars the same way they did in the Solar System, many objects the size of 'Oumuamua should get slung out into space.

Putting the pieces of these observation together, astronomers concluded that the asteroid is like nothing they've ever seen before.

Originally known as A2017 U1, the odd object from beyond was first discovered by Karen Meech and her team from University of Hawaii's Institute for Astronomy, using the Pan-STARRS1 survey telescope on Haleakala in Hawai'i.

"This unusually large variation in brightness means that the object is highly elongated: about ten times as long as it is wide, with a complex, convoluted shape".

"For decades we've theorised that such interstellar objects are out there, and now - for the first time - we have direct evidence they exist", said astrophysicist Thomas Zurbuchen from NASA. This hue is similar to that of objects found in the Kuiper Belt, in the outer part of our solar system, but its orbit and shape firmly place it in the category of interstellar origin. It could be up to 10 times as long as it is wide - a shape never before seen in an asteroid. What they saw, reported today in Nature, was both familiar and extraordinary.

But Vega was not even close to its present position 300,000 years ago, when its journey would have started.

Those properties suggested the asteroid was dense, comprised of rock and possibly metals, had no water or ice, and that its surface was reddened due to the effects of irradiation from cosmic rays over hundreds of millions of years, Nasa said.

On October 19, the Pan-STARRS 1 telescope on Haleakala spotted something odd zooming through our solar system.

"We are continuing to observe this unique object, and we hope to more accurately pin down where it came from and where it is going next on its tour of the galaxy", observation team member Olivier Hainaut, from ESO in Garching, Germany, said in the ESO statement.

These visitors usually only stay for a few weeks at most, careening around the sun and speeding back out into the cosmos; a brief moment of connection and another ten million years of silence. "And now that we have found the first interstellar rock, we are getting ready for the next ones", Hainaut said.

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